1. Field of the Invention
This invention relates to improved aqueous liquid laundry detergent compositions.
2. Background Information Including Description of Related Art
Laundry detergent compositions are sold as either solid, i.e., powder or granular compositions, or liquid compositions. The advantages of liquid over solid compositions are that the caking tending to occur with solid compositions is avoided, the liquid composition is more easily dispersed in wash water, and a liquid is more easily measured and added to the washing machine without spillage than is a solid composition. However, a disadvantage in the use of many liquid detergent compositions as with solid compositions is the phenomenon of soil redeposition, i.e., the tendency of soil which is separated from the articles being washed by the detergency action of the composition, to redeposit on the washed articles causing them to appear dingy after several washings. Thus, any expedient which has the effect of reducing soil redeposition in liquid detergents is very desirable.
U.S. Pat. No. 4,521,332, issued Jun. 4, 1985 to Milora, discloses a highly alkaline aqueous cleaning dispersion useful for cleaning steel prior to various process operations, and comprising sodium hydroxide, a bulking agent such as sodium carbonate, and a polyacrylate acid dispersing agent.
U.S. Pat. No. 5,004,557, issued Apr. 2, 1991 to Nagarajan et al. teaches aqueous liquid laundry detergent compositions comprising a surfactant, a water-soluble sequester builder, and 0.1 to 2% of a homopolymer or copolymer of acrylic acid having a molecular weight in excess of 100,000, as an anti-redeposition and viscosity control agent.
U.S. Pat. No. 5,308,530, issued May 3, 1994 to Aronson et al., discloses a liquid detergent composition comprising calcium-stabilized enzymes and as a builder or anti-redeposition agent, a copolymer of an unsaturated carboxylic acid and a hydrophobic monomer prepared by solution polymerization.
U.S. Pat. No. 5,376,300, issued Dec. 27, 1994 to Bolkan et al., teaches a powdered laundry detergent comprising at least 70 wt. % of a carbonate salt builder, a small amount of a phosphorous-containing sequestering agent and about 0.1 to 2 wt. % of an at least partially neutralized polymer of an unsaturated carboxylic acid.